Sensing device

ABSTRACT

A sensing device includes a substrate, a sensing component and a shielding device. The sensing component is configured to detect a touch capacitance in response to a touch event on the sensing device. The shielding device, between the substrate and the sensing component, is configured to distribute electrical energy, and shield the substrate from the sensing component.

TECHNICAL FIELD

The present disclosure is generally related to an electronic device and,more particularly, to a sensing device.

BACKGROUND

Nowadays, touch devices are widely used in conjunction with electronicdevices. For example, touch devices have been applied to smart phonesand laptop computers. With touch devices, a user can easily operate asmart phone or laptop computer. While touch devices bring a new era ofuser interface, touch sensitivity has been the subject of interest indeveloping advanced touch devices.

SUMMARY

Embodiments of the present disclosure provide a sensing device includesa substrate, a sensing component and a shielding device. The sensingcomponent is configured to detect a touch capacitance in response to atouch event on the sensing device. The shielding device, between thesubstrate and the sensing component, is configured to distributeelectrical energy, and shield the substrate from the sensing component.

In an embodiment, the sensing component and the shielding device areconfigured to define a capacitance for storing electrical energy.

In another embodiment, the shielding device includes a first conductivecomponent over the substrate, and a second conductive component betweenthe substrate and the first conductive component. The second conductivecomponent is configured to define a capacitance, together with the firstconductive component, for storing electrical energy.

In yet another embodiment, the sensing component is fully shielded fromthe substrate by the first and second conductive components.

In still another embodiment, a distance between the first conductivecomponent and the sensing component is smaller than that between thefirst conductive component and the second conductive component.

In yet still another embodiment, the first conductive component isconfigured to overlap a portion of the sensing component.

In further another embodiment, the sensing component is overlapped bythe first conductive component in an overlap ratio of K. A differencebetween a first voltage level at the sensing component with the touchcapacitance detected and a second voltage level at the sensing componentwithout the touch capacitance detected is a function of K.

In still further another embodiment, the difference can be expressedbelow.

${\Delta \; V\; 1} = \frac{{- {VDD}} \times {CF}}{\left\lbrack {\left( {C\; 1 \times \frac{{\left( {1 - K} \right)D\; 1} + {{K \cdot D}\; 3}}{{K \cdot D}\; 3}} \right) + {CF}} \right\rbrack \times \left\lbrack {1 + \frac{\left( {1 - K} \right) \times D\; 1}{K \times D\; 3}} \right\rbrack}$

where ΔV1 represents the difference between the first voltage level andthe second voltage level, VDD represents a supply voltage, CF representsthe touch capacitance, D1 represents a distance between the firstconductive component and the second conductive component, and D3represents a distance between the sensing component and the substrate.

In a yet further embodiment, the first and second conductive componentsare disposed between the substrate and the sensing component.

In a still yet embodiment, in response to an event that the shieldingdevice distributes electrical energy, a voltage level of the firstconductive component is the same as that of the sensing component.

In a further yet embodiment, the second conductive component and thesubstrate are coupled to a reference voltage.

In a still further yet embodiment, the shielding device includes aconductive component. The conductive component is configured to shieldthe substrate from the sensing component. The conductive component andthe substrate are configured to define a capacitance for storingelectrical energy.

In an additional embodiment, the sensing component is fully shieldedfrom the substrate by the conductive component.

In a further embodiment again, the conductive component is disposedbetween the sensing component and the substrate.

In a further additional embodiment, the conductive component isconfigured to overlap a portion of the sensing component.

In a still further another additional embodiment, the sensing componentis overlapped by the conductive component in an overlap ratio of K,wherein a difference between a first voltage level at the sensingcomponent with the touch capacitance detected and a second voltage levelat the sensing component without the touch capacitance detected is afunction of K.

The sensing device of the invention provides a better touch sensitivityby decreasing a capacitance defined by a sensing component for detectinga capacitance in response to a touch event and a substrate.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter. It should be appreciated by those skilled in the art thatthe conception and specific embodiment disclosed may be readily utilizedas a basis for modifying or designing other structures or processes forcarrying out the same purposes of the present invention. It should alsobe realized by those skilled in the art that such equivalentconstructions do not depart from the spirit and scope of the inventionas set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Details of one or more embodiments of the disclosure are set forth inthe accompanying drawings and the description below. Other features andadvantages of the disclosure will be apparent from the description,drawings and claims.

FIG. 1A is a top view of a sensing device.

FIG. 1B is a schematic diagram of an exemplary sensing unit of thesensing device shown in FIG. 1A in prior art.

FIG. 1C is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a first phase.

FIG. 1D is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a second phase in the absence of a touchcapacitance.

FIG. 1E is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a second phase in the presence of a touchcapacitance.

FIG. 2 is a schematic diagram of an exemplary sensing unit of a sensingdevice, in accordance with some embodiments of the present disclosure.

FIG. 3A is a schematic diagram of an exemplary sensing unit of a sensingdevice, in accordance with some embodiments of the present disclosure.

FIG. 3B is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a first phase, in accordance with someembodiments of the present disclosure.

FIG. 3C is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a second phase in the absence of a touchcapacitance, in accordance with some embodiments of the presentdisclosure.

FIG. 3D is a circuit diagram of an equivalent circuit of the exemplarysensing unit operating in a second phase in the presence of a touchcapacitance, in accordance with some embodiments of the presentdisclosure.

FIG. 4 is a schematic diagram of a sensing unit of a sensing device, inaccordance with some embodiments of the present disclosure.

DETAIL DESCRIPTION

In order to make the disclosure completely comprehensible, detailedsteps and structures are provided in the following description.Obviously, implementation of the disclosure does not limit specialdetails known by persons skilled in the art. In addition, knownstructures and steps are not described in detail, so as not to limit thedisclosure unnecessarily. Preferred embodiments of the disclosure willbe described below in detail. However, in addition to the detaileddescription, the disclosure may also be widely implemented in otherembodiments. The scope of the disclosure is not limited to the detaileddescription, and is defined by the claims.

FIG. 1A is a top view of an exemplary sensing device 1. The sensingdevice 1 is adapted to work with an electronic device, such as a smartphone, a laptop computer, a personal digital assistant or a tablet.Referring to FIG. 1A, the sensing device 1 includes a sensing arrayhaving a plurality of sensing units 10 covered by a passivation layer12. The sensing units 10 are configured to sense a touch event of anobject 11, such as a finger or a touch pen, touching the sensing device1 via the passivation layer 12.

FIG. 1B is a schematic circuit diagram of an exemplary sensing unit 10of the sensing device 1 shown in FIG. 1A in prior art. Referring to FIG.1B, the sensing device 1 includes a substrate 16, on which the sensingunits 10 are disposed. For illustration, only one sensing unit 10 isshown in FIG. 1B.

The sensing unit 10 includes a sensing component 14, a capacitor CA andswitches SA, SB and SC. The sensing component 14 detects a touchcapacitance CF associated with the object 11 in response to a touchevent on the sensing device 1. Moreover, the sensing component 14 andthe substrate 16 define a capacitance Csub therebetween, which is aparasitic capacitance. The substrate 16 is substantially kept at areference voltage GND.

For convenience, a same reference numeral or label is used to refer to acapacitor or, when appropriate, its capacitance throughout thedisclosure, and vice versa. For example, while the reference label “CA”as above mentioned refers to a capacitor, it may represent the value ofthe capacitor.

The capacitor CA is charged by a supply voltage VDD, and accordinglystore electrical energy when the switch SA is conducted. The capacitorCA, coupled between the supply voltage VDD and a reference voltage GND,may not be integrated with the sensing component 14 and the switches SA,SB and SC in a single chip or an integrated circuit. For example, thecapacitor CA is mounted on a mother board to communicate with (or coupleto) the sensing component 14 and the switches SA, SB, and SC. Suchcapacitor CA may consume a relatively large area and thus is not areaefficient.

Operation of the sensing unit 10 includes two phases. In the firstphase, when the switch SA is conducted, the capacitor CA is charged bythe supply voltage VDD, and accordingly stores the electrical energy.Meanwhile, the switch SB is not conducted, and the switch SC isconducted. As a result, a voltage level of the sensing component 14 isreset to the reference voltage GND. An equivalent circuit of the sensingunit 10 operating in the first phase is illustrated in FIG. 1C.

In the second phase, the switches SA and SC are not conducted, and theswitch SB is conducted. The electrical energy stored in the capacitor CAin the first phase is distributed among the capacitor CA, thecapacitance Csub and the touch capacitance CF. An equivalent circuit ofthe sensing unit 10 operating in the second phase is illustrated inFIGS. 1D and 1E.

FIG. 1C is a circuit diagram of an equivalent circuit of the exemplarysensing unit 10 operating in the first phase. Referring to FIG. 1C, thecapacitor CA is charged by the supply voltage VDD, and electrical energyis stored in the capacitor CA. Charge in the capacitor CA can beexpressed in equation (1) below.

Q1_((PH1)) =VDD×CA  (1)

where Q1_((PH1)) represents the charge in the capacitor CA.

FIG. 1D is a circuit diagram of an equivalent circuit of the exemplarysensing unit 10 operating in the second phase in the absence of thetouch capacitance CF. Referring to FIG. 1D, the electrical energy storedin the capacitor CA is distributed between the capacitors CA and Csub,which satisfies equation (2) below.

Q1_((PH2)) =Vn1_((PH2))×(Csub+CA)  (2)

where Q1_((PH2)) represents the total charge in the capacitors CA andCsub in phase 2 and Vn1_((PH2)) represents a voltage level at node n1 inphase 2.

Based on the law of charge conservation, the charge Q1_((PH1)) in phase1 equals in quantity to the charge Q1_((PH2)) in phase 2. Based onequations (1) and (2), the voltage level Vn1_((PH2)) at node n1 in phase2 can be expressed in equation (3) below.

$\begin{matrix}{{{Vn}\; 1} = \frac{{VDD} \times {CA}}{\left( {{Csub} + {CA}} \right)}} & (3)\end{matrix}$

FIG. 1E is a circuit diagram of an equivalent circuit of the exemplarysensing unit 10 operating in the second phase in the presence of thetouch capacitance CF. Referring to FIG. 1E, electrical energy stored inthe capacitor CA is distributed among the capacitors CA, Csub and CF.For the similar rationale as provided in the description of FIG. 1C, avoltage level Vn1′_((PH2)) at node n1 in phase 2 with the touchcapacitance CF detected can be expressed in equation (4) below.

$\begin{matrix}{{{Vn}\; 1_{({{PH}\; 2})}^{\prime}} = \frac{{VDD} \times {CA}}{\left( {{Csub} + {CA} + {CF}} \right)}} & (4)\end{matrix}$

By subtracting the voltage level Vn1_((PH2)) from the voltage levelVn1′_((PH2)), touch sensitivity can be determined. Difference (ΔV)between the voltage levels Vn1_((PH2)) and Vn1′_((PH2)) can be expressedin equation (5) below.

$\begin{matrix}{{\Delta \; V} = \frac{{- {VDD}} \times {CF}}{\left( {{Csub} + {CA} + {CF}} \right)\left( {1 + \frac{Csub}{CA}} \right)}} & (5)\end{matrix}$

Since the difference ΔV relates to the touch sensitivity of a sensingdevice, it is desirable to have a larger difference ΔV in order toachieve a higher touch sensitivity. That is, a relatively largedifference facilitates the detection of a touch event. In view ofequation (5), a possible way to increase the difference ΔV is todecrease the capacitance Csub in the denominator.

FIG. 2 is a schematic diagram of an exemplary sensing unit 20 of asensing device 2, in accordance with some embodiments of the presentdisclosure. The sensing device 2 includes a plurality of the sensingunits and a detection device 28. For the sake of convenience ofillustration, only one sensing unit 20 is shown in FIG. 2. Referring toFIG. 2, the sensing unit 20 includes a sensing component 24 and ashielding device 22. The detection device 28, coupled to the pluralityof sensing units 20, is configured to detect a voltage level at thesensing component 24 of the sensing unit 20 and determine if there is atouch event on the sensing device 2 based on a change in the voltagelevel. The detection device 28 includes, for example, a processor or acentral processing unit (CPU).

The sensing component 24 is configured to, in response to a touch eventon the sensing device 2, detect a touch capacitance CF associated withthe object 11. Furthermore the sensing component 24 may be positioned ina metal 1 (M1) layer, a metal 2 (M2) layer or other suitable conductivelayers over the substrate 16.

The shielding device 22 operates in a power domain of supply voltage VDDand reference voltage GND. Moreover, the shielding device 22 isconfigured to shield or mask the substrate 16 from the sensing component24, or vice versa. Specifically, the shielding device 22 overlaps thesensing component 24 in physical structure so that efficient capacitancebetween the sensing component 24 and the substrate 16 is decreased,thereby increasing the touch sensitivity, as will be further discussed.In some embodiments, the shielding device 22 fully overlaps the sensingcomponent 24. In some embodiments, the shielding device 22 overlaps aportion of the sensing component 24, and exposes the unshielded portionof the sensing component 24 to the substrate 16.

Furthermore, the shielding device 22 and the sensing component 24 areconfigured to define a capacitor C for storing electrical energy whenthe shielding device 22 is charged by the supply voltage VDD. Moreover,a capacitor Csub′ is defined between the sensing component 24 and thesubstrate 16. The stored electrical energy is distributed between thecapacitors C and Csub′.

Since at least a portion of the sensing component 24 is overlapped bythe shielding device 22 and thus is shielded from the substrate 16, theeffective capacitance Csub′ is lower than the capacitance Csub describedand illustrated with reference to FIG. 1B. In that case, voltagevariation in the sensing component 24 becomes more significant and avoltage difference becomes more sensitive. Effectively, as previouslydiscussed with respect to equation (5), a touch event can be more easyto detect, which will be described in detail with reference to FIGS. 3Ato 3D.

FIG. 3A is a schematic diagram of an exemplary sensing unit 30 of asensing device 3, in accordance with some embodiments of the presentdisclosure. Referring to FIG. 3A, the sensing device 3 is similar to thesensing device 2 described and illustrated with reference to FIG. 2except that, for example, the sensing unit 30 includes a firstconductive component 36, a second conductive component 38, and switchesS1, S2 and S3. The first conductive component 36 and the secondconductive component 38 serve as a shielding device 32 between thesensing component 24 and the substrate 16. Moreover, the firstconductive component 36 and the second conductive component 38 may bedisposed in, for example, a metal 2 (M2) layer and a metal 1 (M1) layer,respectively, or in other different conductive layers. In an embodiment,the first conductive component 36 has substantially the same size as thesecond conductive component 38.

The first conductive component 36 and the second conductive component 38are configured to define a first capacitance C1 for storing electricalenergy. The first conductive component 36 and the second conductivecomponent 38 are spaced apart by a distance D1, which is a factor ofdetermining the first capacitance C1. The first capacitance C1 can beexpressed in equation (6) below.

$\begin{matrix}{{C\; 1} = {ɛ\frac{A\; 1}{D\; 1}}} & (6)\end{matrix}$

where ∈ represents the dielectric constant of the material between thefirst conductive component 36 and the second conductive component 38,and A1 represents an area of a surface A36 of the first conductivecomponent 36 (and also represents an area of a surface A38 of the secondconductive component 38).

Moreover, the first conductive component 36 and the sensing component 24are configured to define a second capacitance C2 for storing electricalenergy. The first conductive component 36 and the sensing component 24are spaced apart by a distance D2, which is a factor of determining thesecond capacitance C2. In an embodiment, the distance D2 is shorter thanthe distance D1. Given that a distance D3 between the sensing component24 and the substrate 16 is fixed, the distance D1 increases as thedistance D2 decreases, thereby decreasing the first capacitance C1 andhence increasing the touch sensitivity, as will be further discussed.

In addition, the second conductive component 38 is coupled to thereference ground GND. As such, the voltage between the second conductivecomponent 38 and the substrate 16 is ideally equal to zero. Therefore, aspace between the second conductive component 38 and the substrate 16 isfree of any capacitance.

Additionally, the sensing component 24 and the substrate 16 areconfigured to define a capacitance b1. The sensing component 24 and thesubstrate 16 are spaced apart by a distance D3, which is a factor ofdetermining the capacitance b1.

The first conductive component 36 and the second conductive component 38are configured to shield the substrate 16 from the sensing component 24,and vice versa. Accordingly, the capacitance b1 can be expressed inequation (7) below.

$\begin{matrix}\begin{matrix}{{{b\; 1} = {ɛ\frac{\left( {{A\; 2} - {A\; 1}} \right)}{D\; 3}}},{{{where}\mspace{14mu} \frac{A\; 1}{A\; 2}} = K},{K \leq 1}} \\{= {ɛ\frac{A\; 2\left( {1 - K} \right)}{D\; 3}}}\end{matrix} & (7)\end{matrix}$

where A2 represents an area of a surface A24 of the sensing component24, the term (A2−A1) represents an effective area, which means the areaof the surface A24 unshielded by the first conductive component 36 orthe second conductive component 38 and thus exposed to the substrate 16,and K is a ratio of the area of the surface A36 of the first conductivecomponent 36 to that of the surface A24 of the sensing component 24. K,having a value not greater than one, represents a percentage that thesensing component 24 is overlapped or shielded by the first conductivecomponent 36. Specifically, the sensing component 24 is overlapped bythe first conductive component 36 in an overlap ratio of K. When K issmaller than 1, a portion of the surface A24 of the sensing component 24is shielded. When K equals 1, the sensing component 24 is entirelyshielded by the first conductive component 36 or the second conductivecomponent 38.

Based on equations (6) and (7), the capacitance b1 can be rearranged inequation (8) below.

$\begin{matrix}{{b\; 1} = {C\; 1\frac{D\; 1}{K}\frac{\left( {1 - K} \right)}{D\; 3}}} & (8)\end{matrix}$

In the present embodiment, the first conductive component 36 isconfigured to shield a portion of the sensing component 24 from thesubstrate 16, and the unshielded portion of the sensing component 24 isexposed to the substrate 16.

The switches S1 and S2 are configured to be conducted when switch S3 isnot conducted, and vice versa. Each of the switches S1, S2 and S3includes, for example, a field-effect transistor (FET), or ametal-Oxide-Semiconductor field-effect transistor (MOSFET).

Operation of the sensing unit 30 includes two phases. In the firstphase, the switch S1 is conducted, and the first and second capacitorsC1 and C2 are charged by a supply voltage VDD, and accordingly storeelectrical energy. Meanwhile, since the switch S3 is not conducted andthe switch S2 is conducted, the sensing component 24 is reset to thereference voltage GND. An equivalent circuit of the sensing unit 30operating in the first phase is illustrated in FIG. 3B.

In the second phase, the switches S1 and S2 are not conducted, and theswitch S3 is conducted. Electrical energy stored in the capacitors C1and C2 in the first phase is distributed among the capacitors C1, b1 andCF. Since the switch S3 is conducted, the voltage level at the sensingcomponent 24 is the same as that at the first conductive component 36.An equivalent circuit of the sensing unit 30 operating in the secondphase is illustrated in FIGS. 3C and 3D.

FIG. 3B is a circuit diagram of the equivalent circuit of the exemplarysensing unit 30 operating in the first phase. Referring to FIG. 3B, asthe first and second capacitors C1 and C2 are charged by the supplyvoltage VDD, charge stored in the first and second capacitors C1 and C2can be expressed in equations (9) and (10) below.

QNA _((PH1)) =VDD×(C1)+VDD×(C2)  (9)

QNB _((PH1)) =−VDD×(C2)  (10)

where QNA_((PH1)) represents the positive charge stored in the first andsecond capacitors C1 and C2 at the side of a node nA in phase 1, andQNB_((PH1)) represents the negative charge stored in C2 at the side of anode nB in phase 1.

FIG. 3C is a diagram of the equivalent circuit of the exemplary sensingunit 30 operating in the second phase in the absence of the touchcapacitance CF. Referring to FIG. 3C, due to the conducted state of theswitch S3 in the second phase, a voltage level at node nA is the same asthat at node nB. As a result, the voltage across the second capacitor C2is zero and thus electrical energy is no longer stored in the secondcapacitor C2. Electrical energy stored in the first and secondcapacitors C1 and C2 in the first phase are distributed between thefirst capacitor C1 and the capacitor b1, which observes equation (11)below.

QNA _((PH2)) =VnA _((PH2))×(b1+C1)  (11)

where QNA_((PH2)) represents the charge stored in the first capacitor C1and the capacitor b1 in phase 2, and VnA_((PH2)) represents a voltagelevel at node nA in phase 2 in the absence of the touch capacitance CF.

Based on the law of charge conservation, equation (12) is obtainedbelow.

QNA _((PH2)) =QNA _((PH1)) +QNB _((PH1))  (12)

Based on equations (9), (10), (11) and (12), the voltage levelVnA_((PH2)) at node nA in phase 2 can be expressed in equation (13)below.

$\begin{matrix}{{VnA}_{({{PH}\; 2})} = \frac{{VDD} \times C\; 1}{\left( {{C\; 1} + {b\; 1}} \right)}} & (13)\end{matrix}$

FIG. 3D is a circuit diagram of the equivalent circuit of the exemplarysensing unit 30 operating in the second phase in the presence of thetouch capacitance CF. Referring to FIG. 3D, electrical energy stored inthe first and second capacitors C1 and C2 is distributed among the firstcapacitor C1, the capacitor b1 and the touch capacitor CF. For thesimilar rationale as provided in the description of FIG. 3C, a voltagelevel at node nA in phase 2 with the touch capacitance CF detected canbe expressed in equation (14) below.

$\begin{matrix}{{VnA}^{\prime} = \frac{{VDD} \times C\; 1}{\left( {{b\; 1} + {C\; 1} + {CF}} \right)}} & (14)\end{matrix}$

where VnA′ represents the voltage level at node n1 in phase 2 with thetouch capacitance CF detected.

By subtracting the voltage level VnA from the voltage level VnA′, touchsensitivity can be determined. Difference (ΔV1) between the voltagelevels VnA and VnA′ is expressed in equation (15) below.

$\begin{matrix}{{\Delta \; V\; 1} = \frac{{- {VDD}} \times {CF}}{\left( {{b\; 1} + {C\; 1} + {CF}} \right)\left( {1 + \frac{b\; 1}{C\; 1}} \right)}} & (15)\end{matrix}$

Compared equation (15) with equation (5), ΔV1 is greater than ΔV for atleast the reasons as follows. Firstly, for the capacitance definedbetween the sensing component and the substrate, Csub in equation (5) isgreater than b1 in equation (15). As previously discussed, in theembodiment of FIG. 3A, the sensing component 24 is shielded by the firstconductive component 36 and the second conductive component 38.Therefore, the capacitance b1 in equation (15) is lower than thecapacitance Csub in equation (5). As a result, the difference (ΔV1)described in the embodiment of FIG. 3A is greater than the difference(ΔV) described and illustrated with reference to FIG. 1B. Since a largerdifference results in a higher sensitivity, a touch event can be moreeasy to detect by the sensing unit 30 of the embodiment shown in FIG.3A.

Secondly, for the capacitance charged by a supply voltage, CA inequation (5) is greater than C1 in equation (15). Generally, thecapacitance of the capacitor CA not integrated in a sensing unit isgreater than that of the capacitance C1 defined in an integratedcircuit. Moreover, as previously discussed, by a proper arrangement ofthe first conductive component 36 and the second conductive component 38in layout design of the sensing unit 30, a relatively small or desirablefirst capacitance C1 can be achieved. With the relatively smallcapacitance C1, the difference (ΔV1) described in the embodiment of FIG.3A is greater than the difference (ΔV) described and illustrated withreference to FIG. 1B. As a result, a touch event can be more easy todetect by the sensing unit 30 of the embodiment shown in FIG. 3A.

Further, by substituting b1 in equation (8) into equation (15), thedifference (ΔV1) can be further expressed in equation (16) as follows:

$\begin{matrix}\begin{matrix}{{\Delta \; V\; 1} = \frac{{- {VDD}} \times {CF}}{\left( {\left( {C\; 1\frac{\left( {1 - K} \right)D\; 1}{K \times D\; 3}} \right) + {C\; 1} + {CF}} \right)\left( {1 + {\frac{D\; 1}{K} \times \frac{1 - K}{D\; 3}}} \right)}} \\{= \frac{{- {VDD}} \times {CF}}{\left\lbrack {\left( {C\; 1 \times \frac{{\left( {1 - K} \right)D\; 1} + {{KD}\; 3}}{{KD}\; 3}} \right) + {CF}} \right\rbrack \times \left\lbrack {1 + \frac{\left( {1 - K} \right) \times D\; 1}{K \times D\; 3}} \right\rbrack}}\end{matrix} & (16)\end{matrix}$

Based on equation (16), it can be found that the difference (ΔV1) is afunction of K.

FIG. 4 is a schematic diagram of an exemplary sensing unit 40 of asensing device 4, in accordance with some embodiments of the presentdisclosure. Referring to FIG. 4, the sensing unit 40 is similar to thesensing unit 30 described and illustrated with reference to FIG. 3Aexcept that, for example, the sensing unit 40 includes a shieldingdevice 42 formed by a single conductive component 44. The conductivecomponent 44 may be disposed in, for example, a metal 1 (M1) layer, oranother conductive layer over the substrate 16. For illustration, onlyone sensing unit 40 is shown in FIG. 4.

The conductive component 44, disposed between the sensing component 24and the substrate 16, is configured to shield the substrate 16 from thesensing component 24, and vice versa. In some embodiments, the substrate16 is fully shielded from the sensing component 24 by the conductivecomponent 44. In other embodiments, the conductive component 44 isconfigured to shield or mask a portion of the sensing component 24.

Moreover, the conductive component 44 and the sensing component 24 areconfigured to define a capacitance C4 for storing electrical energy. Theconductive component 44 and the sensing component 24 are spaced apart bya distance D4, which is a factor of determining the capacitance C4.

The conductive component 44 and the substrate 16 are configured todefine a capacitance C5 for storing electrical energy. The conductivecomponent 44 and the substrate 16 are spaced apart by a distance D5,which is a factor of determining the capacitance C5. In someembodiments, the distance D5 is longer than the distance D4. In thatcase, as previously discussed, the capacitance C5 is relatively small,which facilitates the detection of a touch event. Compared with theembodiment of FIG. 3A, since in the present embodiment only oneconductive component (i.e., the conductive component 44) is presentbetween the sensing component 24 and the substrate 16, the distance D5between the sensing component 24 and the substrate 16 can be adjusted tobe relatively long in the layout design. As a result, the capacitance C5can be relatively small.

Based on the similar discussion in the embodiment of FIG. 3A, thedifference (ΔV2) between a voltage level at the conductive component 44with a touch capacitance CF detected and a voltage level at theconductive component 44 without the touch capacitance CF being detectedcan be expressed in equation (17) below.

$\begin{matrix}{{\Delta \; V\; 2} = \frac{{- {VDD}} \times {CF}}{\left( {{b\; 1} + {C\; 5} + {CF}} \right)\left( {1 + \frac{b\; 1}{C\; 5}} \right)}} & (17)\end{matrix}$

Compared equation (17) with equation (15), given that the conductivecomponent 44 has the same size as the first conductive component 36 andthe second conductive component 38, the capacitance for storingelectrical, C1 in equation (15) and C5 in equation (17), is different.Due to the relatively long distance D5, the capacitance C5 in equation(17) is smaller, resulting in a higher sensitivity.

Although in language specific to structural features and/ormethodological acts of the subject matter has been described, it is tobe understood that the appended claims is not necessarily limited to thesubject matter defined the specific features or acts described above.Rather, the specific features and acts described above as example formsof implementing the claims are disclosed.

Various operations of embodiments are provided herein. The order inwhich some or all of the operations are described should not beconstrued as to imply that these operations are necessarily orderdependent. Alternative ordering will be appreciated given the benefit ofthis description. Further, it will be understood that not all operationsare necessarily present in each embodiment provided herein. Also, itwill be understood that not all operations are necessary in someembodiments.

It will be appreciated that layers, features, elements, etc. depictedherein are illustrated with particular dimensions relative to oneanother, such as structural dimensions or orientations, for example, forpurposes of simplicity and ease of understanding and that actualdimensions of the same differ substantially from that illustratedherein, in some embodiments.

Although the disclosure has been shown and described with respect to oneor more implementations, equivalent alterations and modifications willoccur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A sensing device, comprising: a substrate; asensing component, configured to detect a touch capacitance in responseto a touch event on the sensing device; and a shielding device betweenthe substrate and the sensing component, configured to distributeelectrical energy, and shield the substrate from the sensing component.2. The sensing device of claim 1, wherein the sensing component and theshielding device are configured to define a capacitance for storingelectrical energy.
 3. The sensing device of claim 1, wherein theshielding device comprises: a first conductive component over thesubstrate; and a second conductive component between the substrate andthe first conductive component, configured to define a capacitancetogether with the first conductive component, for storing electricalenergy.
 4. The sensing device of claim 3, wherein the sensing componentis fully shielded from the substrate by the first and second conductivecomponents.
 5. The sensing device of claim 3, wherein a distance betweenthe first conductive component and the sensing component is smaller thanthat between the first conductive component and the second conductivecomponent.
 6. The sensing device of claim 3, wherein the firstconductive component is configured to overlap a portion of the sensingcomponent.
 7. The sensing device of claim 3, wherein the sensingcomponent is overlapped by the first conductive component in an overlapratio of K, wherein a difference between a first voltage level at thesensing component with the touch capacitance detected and a secondvoltage level at the sensing component without the touch capacitancedetected is a function of K.
 8. The sensing device of claim 7, whereinthe difference can be expressed as follows:${\Delta \; V\; 1} = \frac{{- {VDD}} \times {CF}}{\left\lbrack {\left( {C\; 1 \times \frac{{\left( {1 - K} \right)D\; 1} + {{KD}\; 3}}{{KD}\; 3}} \right) + {CF}} \right\rbrack \times \left\lbrack {1 + \frac{\left( {1 - K} \right) \times D\; 1}{K \times D\; 3}} \right\rbrack}$where ΔV1 represents the difference between the first voltage level andthe second voltage level, VDD represents a supply voltage, CF representsthe touch capacitance, D1 represents a distance between the firstconductive component and the second conductive component, and D3represents a distance between the sensing component and the substrate.9. The sensing device of claim 3, wherein the first and secondconductive components are disposed between the substrate and the sensingcomponent.
 10. The sensing device of claim 3, wherein in response to anevent that the shielding device distributes electrical energy, a voltagelevel of the first conductive component is the same as that of thesensing component.
 11. The sensing device of claim 3, wherein the secondconductive component and the substrate are coupled to a referencevoltage.
 12. The sensing device of claim 1, wherein the shielding devicecomprises: a conductive component, configured to shield the substratefrom the sensing component, wherein the conductive component and thesubstrate are configured to define a capacitance for storing electricalenergy.
 13. The sensing device of claim 12, wherein the sensingcomponent is fully shielded from the substrate by the conductivecomponent.
 14. The sensing device of claim 12, wherein the conductivecomponent is disposed between the sensing component and the substrate.15. The sensing device of claim 12, wherein the conductive component isconfigured to overlap a portion of the sensing component.
 16. Thesensing device of claim 12, wherein the sensing component is overlappedby the conductive component in an overlap ratio of K, wherein adifference between a first voltage level at the sensing component withthe touch capacitance detected and a second voltage level at the sensingcomponent without the touch capacitance detected is a function of K.